Medium 5.3Published Apr 20, 2026

CVE-2026-6608lm-sys fastchat Arena Side-by-Side View add_text control flow

Updated under an hour ago (Oct 27, 2026, 5:20 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for lm-sys fastchat

Exploited in the last 30 days

A vulnerability was detected in lm-sys fastchat up to 0.2.36. Impacted is the function add_text of the component Arena Side-by-Side View Handler. The manipulation results in incorrect control flow. The attack can be launched remotely. The exploit is now public and may be used. The root cause was fixed in commit 34eca62 for gradio_block_arena_named.py, but three other files were missed.

CVSS: 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
Weakness (CWE): CWE-670
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulDB
NVD analysis: Deferred
Record last updated: Apr 20, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

lm-sys fastchat lm-sys:fastchat	0.2.0; 0.2.1; 0.2.2; 0.2.3; 0.2.4; 0.2.5; 0.2.6; 0.2.7; and 29 more ranges	CNA record

References

References

https://vuldb.com/vuln/358243	vdb-entry, technical-description
https://vuldb.com/vuln/358243/cti	signature, permissions-required
https://vuldb.com/submit/792228	third-party-advisory
https://github.com/lm-sys/FastChat/issues/3834	issue-tracking
https://gist.github.com/YLChen-007/e45039d23e698222d887ee09735d9d36	exploit
https://github.com/lm-sys/FastChat/	product

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.